The scons configure script assumes that, for OS X 10.7 and earlier, that the gcc in Xcode is named gcc-4.2. In Xcode 4.3, this changed to gcc. The logic for Xcode 4.4 on OS X 10.8 is correct. Making it use the name "gcc" instead of "gcc-4.2" (and similarly for g++) lets it compile correctly.

The attached patch forces the names "gcc" and "g++" for Xcode 4.3 and higher, regardless of OS X version.